An anti-vibration rubber composition has been generally used in an automobile for the purpose of reducing vibration or noise. The anti-vibration rubber composition is sometimes required to have, for example, flame retardancy as a property in addition to an anti-vibration property. A general approach to making a rubber flame-retardant is to add a flame retardant, such as a halogen-based flame retardant, a phosphorus-based flame retardant, or a metal hydroxide (see, for example, Patent Literatures 1 to 3).